1. Field of the Invention
The present invention relates generally to fluorinated ketones.
2. Description of Related Art
Fluorinated ketones are useful intermediates in the synthesis of pharmaceutical products. Fluorinated ketones have been found to degrade upon storage and cannot be used after they have been stored for extended periods without sacrificing yield in subsequent transformations; this causes the process to be economically unfavorable. Of particular interest is 1,1,1-trifluoroacetone, which has been used as an important intermediate for the preparation of biologically active compounds (for example, J. Med. Chem. 1975 (18), 895, J. Med. Chem. 1983 (26), 950 and Bull. Soc. Chim. France 1986, 933).
We have found that 1,1,1-trifluoroacetone is stable if stored in glass containers. However, the low boiling point (21°-22° C.) of 1,1,1-trifluoroacetone makes this problematic on a large scale. Also, shipping a low boiling liquid in glass would not be the most desirable method of shipping such a material. Upon storage in metal containers for a prolonged period of time, 1,1,1-trifluoroacetone shows a substantial amount of degradation. It is known in the prior art that 1,1,1-trifluoroacetone can be stabilized by acids having a pKa of 4 or below (U.S. Pat. No. 6,531,075). The amount of acid that is added plays a critical role, since the presence of excess acid can promote the degradation of trifluoroacetone.
Accordingly, there remains a need in the art to discover other materials that can be used to stabilize fluorinated ketones in general, and 1,1,1-trifluoroacetone in particular.